This invention relates to the use of substituted 2,4-imidazolidinedione compounds for the production of pharmaceutical preparations for the treatment of pain.
Pain is a subjective sensory experience consisting of a sensory component and an affective component. The physiological aspects of the aetiology of pain comprise reception of any physical/chemical stimulus of a potentially tissue-threatening intensity by activation of the so-called nociceptors, specific uni- or polymodal nocisensors of high-threshold primary ascending neural pathways. When considering the pathophysiological aspects of the aetiology of pain, all the components of the nociceptive system may be altered: reception by nocisensors, transmission to the spinal level, perception, awareness and processing at the supraspinal level. Plastic changes or the development of chronic conditions may be brought about not only by disruption of the afferent system but also by disrupted perception and processing and disruption of the descending, controlling, endogenic pain-relieving system. In chronic or neuropathic pain, various phenomena occur including sensitisation of the nocisensors by endogenic or exogenic substances. In the event of persistent stimulation or disruption of the integrity of the nociceptor, not only secondary but also central sensitisation may occur at the spinal level. Such phenomena are known in particular in chronic inflammatory conditions, for example in rheumatoid arthritis. Inflammatory tissue hormones and transmitters (histamine, serotonin, prostaglandins, interleukin-1) secreted by local inflamed cells in the vicinity of the nocisensor may result in sensitisation of the nociceptors with a reduced threshold of stimulus and increased spontaneous activity, wherein persistent inflammation with constant stimuli ultimately results in the development of adaptive processes at the spinal and supraspinal levels.
Substituted 2,4-imidazolidinedione compounds and the immunomodulating action thereof are known from co-pending patent application no. 08/738,232, filed Oct. 25, 1996 (=DE19540027.5), the disclosure of which is incorporated herein by reference.